Objective: Several series report on the relative contribution of ectopic ACTH syndrome (EAS) in the spectrum of Cushing's syndrome. However, prevalence of EAS in patients with thoracic or gastroenteropancreatic neuroendocrine tumors (GEP-NETs) is currently unknown.
Design: We assessed, in a tertiary referral center, the prevalence of EAS in a large cohort of thoracic and GEP-NET patients including clinical, biochemical, and radiological features; management; and treatment outcome. Methods: In total, 918 patients with thoracic or GEP-NETs were studied (1993-2012). Multiple endocrine neoplasia type 1 and small cell lung carcinoma patients were excluded. Differentiation between synchronous, metachronous, and cyclic occurrence of EAS was made.
Results: Out of the 918 patients with thoracic and GEP-NETs, 29 patients. EAS occurred synchronously in 23 patients, metachronously in four patients, and cyclical in two patients respectively. NETs causing EAS included lung/bronchus, pancreatic, and thymic. In four patients, the cause of EAS was unknown. Median overall survival (OS) of non-EAS thoracic and GEP-NET patients was 61.2 months. Median OS of EAS patients was 41.4 months. After comparison, only the first 5-year survival was significantly shorter in EAS patients.
Conclusion: Prevalence of EAS in this large cohort of patients with thoracic and GEP-NETs was 3.2%. EAS was mostly caused by thoracic and pancreatic NETs. First 5-year survival of EAS patients was shorter compared with non-EAS patients.

dx.doi.org/10.1530/EJE-15-0968, hdl.handle.net/1765/82227
European Journal of Endocrinology
Department of Surgery

Kamp, K, Alwani, R.A, Korpershoek, E, Franssen, G, de Herder, W.W, & Feelders, R.A. (2016). Prevalence and clinical features of the ectopic ACTH syndrome in patients with gastroenteropancreatic and thoracic neuroendocrine tumors. European Journal of Endocrinology, 174(3), 271–280. doi:10.1530/EJE-15-0968